diff --git a/.github/workflows/ci-test-backend.yml b/.github/workflows/ci-test-backend.yml
index 8848de99..204be4d5 100644
--- a/.github/workflows/ci-test-backend.yml
+++ b/.github/workflows/ci-test-backend.yml
@@ -33,7 +33,7 @@ jobs:
 
       - name: install golangci-lint and goveralls
         run: |
-          curl -sfL https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh| sh -s -- -b $GITHUB_WORKSPACE v1.25.0
+          curl -sfL https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh| sh -s -- -b $GITHUB_WORKSPACE v1.26.0
           go get -u github.com/mattn/goveralls
 
       - name: test and lint backend
diff --git a/backend/app/migrator/native_test.go b/backend/app/migrator/native_test.go
index 45b3adde..f30b05e7 100644
--- a/backend/app/migrator/native_test.go
+++ b/backend/app/migrator/native_test.go
@@ -180,9 +180,9 @@ func TestNative_ImportManyWithError(t *testing.T) {
 // makes new boltdb, put two records
 func prep(t *testing.T) (ds *service.DataStore, teardown func()) {
 
-	testDb := fmt.Sprintf("/tmp/migrator-%d.db", rand.Intn(999999999))
+	testDB := fmt.Sprintf("/tmp/migrator-%d.db", rand.Intn(999999999))
 
-	boltStore, err := engine.NewBoltDB(bolt.Options{}, engine.BoltSite{SiteID: "radio-t", FileName: testDb})
+	boltStore, err := engine.NewBoltDB(bolt.Options{}, engine.BoltSite{SiteID: "radio-t", FileName: testDB})
 	assert.NoError(t, err)
 
 	b := &service.DataStore{Engine: boltStore, AdminStore: admin.NewStaticStore("12345", nil, []string{}, "")}
@@ -207,6 +207,6 @@ func prep(t *testing.T) (ds *service.DataStore, teardown func()) {
 
 	return b, func() {
 		require.NoError(t, b.Close())
-		_ = os.Remove(testDb)
+		_ = os.Remove(testDB)
 	}
 }
diff --git a/backend/app/rest/api/rest_private_test.go b/backend/app/rest/api/rest_private_test.go
index 4cfc6c05..f4e8fec6 100644
--- a/backend/app/rest/api/rest_private_test.go
+++ b/backend/app/rest/api/rest_private_test.go
@@ -120,8 +120,8 @@ func TestRest_CreateWithRestrictedWord(t *testing.T) {
 	ts, _, teardown := startupT(t)
 	defer teardown()
 
-	badComment := fmt.Sprintf(`{"text": "What the duck is that?", "locator":{"url": "https://radio-t.com/blah1",
-"site": "remark42"}}`)
+	badComment := `{"text": "What the duck is that?", "locator":{"url": "https://radio-t.com/blah1",
+"site": "remark42"}}`
 
 	resp, err := post(t, ts.URL+"/api/v1/comment", badComment)
 	assert.NoError(t, err)
diff --git a/backend/app/rest/api/rest_public.go b/backend/app/rest/api/rest_public.go
index 295a6a3e..d4b085d5 100644
--- a/backend/app/rest/api/rest_public.go
+++ b/backend/app/rest/api/rest_public.go
@@ -164,14 +164,14 @@ func (s *public) infoStreamCtrl(w http.ResponseWriter, r *http.Request) {
 	locator := store.Locator{SiteID: r.URL.Query().Get("site"), URL: r.URL.Query().Get("url")}
 	log.Printf("[DEBUG] start stream for %+v, timeout=%v, refresh=%v", locator, s.streamer.TimeOut, s.streamer.Refresh)
 
-	sinceTs, err := s.parseSince(r)
+	sinceTS, err := s.parseSince(r)
 	if err != nil {
 		rest.SendErrorJSON(w, r, http.StatusBadRequest, err, "can't translate since parameter", rest.ErrDecode)
 		return
 	}
 
 	fn := func() steamEventFn {
-		lastTS := sinceTs
+		lastTS := sinceTS
 		lastCount := 0
 
 		return func() (event string, data []byte, upd bool, err error) {
@@ -245,17 +245,17 @@ func (s *public) lastCommentsStreamCtrl(w http.ResponseWriter, r *http.Request)
 	siteID := r.URL.Query().Get("site")
 	log.Printf("[DEBUG] get last comments stream for %s", siteID)
 
-	sinceTs, err := s.parseSince(r)
+	sinceTS, err := s.parseSince(r)
 	if err != nil {
 		rest.SendErrorJSON(w, r, http.StatusBadRequest, err, "can't translate since parameter", rest.ErrDecode)
 		return
 	}
-	if sinceTs.IsZero() {
-		sinceTs = time.Now()
+	if sinceTS.IsZero() {
+		sinceTS = time.Now()
 	}
 
 	fn := func() steamEventFn {
-		sinceTime := sinceTs
+		sinceTime := sinceTS
 		return func() (event string, data []byte, upd bool, err error) {
 			key := cache.NewKey(siteID).ID(URLKey(r)).Scopes(lastCommentsScope)
 			data, err = s.cache.Get(key, func() ([]byte, error) {
@@ -483,13 +483,13 @@ func (s *public) applyView(comments []store.Comment, view string) []store.Commen
 }
 
 func (s *public) parseSince(r *http.Request) (time.Time, error) {
-	sinceTs := time.Time{}
+	sinceTS := time.Time{}
 	if since := r.URL.Query().Get("since"); since != "" {
 		unixTS, e := strconv.ParseInt(since, 10, 64)
 		if e != nil {
 			return time.Time{}, errors.Wrap(e, "can't translate since parameter")
 		}
-		sinceTs = time.Unix(unixTS/1000, 1000000*(unixTS%1000)) // since param in msec timestamp
+		sinceTS = time.Unix(unixTS/1000, 1000000*(unixTS%1000)) // since param in msec timestamp
 	}
-	return sinceTs, nil
+	return sinceTS, nil
 }
diff --git a/backend/app/rest/api/rest_test.go b/backend/app/rest/api/rest_test.go
index 09599e3b..08bf60f3 100644
--- a/backend/app/rest/api/rest_test.go
+++ b/backend/app/rest/api/rest_test.go
@@ -331,11 +331,11 @@ func TestRest_cacheControl(t *testing.T) {
 
 func startupT(t *testing.T) (ts *httptest.Server, srv *Rest, teardown func()) {
 	tmp := os.TempDir()
-	var testDb string
+	var testDB string
 	// pick a file name which is not in use for sure
 	for i := 0; i < 10; i++ {
-		testDb = fmt.Sprintf("/%s/test-remark-%d.db", tmp, rand.Int31())
-		_, err := os.Stat(testDb)
+		testDB = fmt.Sprintf("/%s/test-remark-%d.db", tmp, rand.Int31())
+		_, err := os.Stat(testDB)
 		if err != nil {
 			break
 		}
@@ -343,7 +343,7 @@ func startupT(t *testing.T) (ts *httptest.Server, srv *Rest, teardown func()) {
 	_ = os.RemoveAll(tmp + "/ava-remark42")
 	_ = os.RemoveAll(tmp + "/pics-remark42")
 
-	b, err := engine.NewBoltDB(bolt.Options{}, engine.BoltSite{FileName: testDb, SiteID: "remark42"})
+	b, err := engine.NewBoltDB(bolt.Options{}, engine.BoltSite{FileName: testDB, SiteID: "remark42"})
 	require.NoError(t, err)
 
 	memCache := cache.NewScache(cache.NewNopCache())
@@ -406,7 +406,7 @@ func startupT(t *testing.T) (ts *httptest.Server, srv *Rest, teardown func()) {
 	teardown = func() {
 		ts.Close()
 		require.NoError(t, srv.DataService.Close())
-		_ = os.Remove(testDb)
+		_ = os.Remove(testDB)
 		_ = os.RemoveAll(tmp + "/ava-remark42")
 		_ = os.RemoveAll(tmp + "/pics-remark42")
 	}
diff --git a/backend/app/store/engine/bolt.go b/backend/app/store/engine/bolt.go
index d0d747ec..0eb11f42 100644
--- a/backend/app/store/engine/bolt.go
+++ b/backend/app/store/engine/bolt.go
@@ -113,8 +113,8 @@ func (b *BoltDB) Create(comment store.Comment) (commentID string, err error) {
 
 		// add reference to comment to "last" bucket
 		lastBkt = tx.Bucket([]byte(lastBucketName))
-		commentTs := []byte(comment.Timestamp.Format(tsNano))
-		if err = lastBkt.Put(commentTs, ref); err != nil {
+		commentTS := []byte(comment.Timestamp.Format(tsNano))
+		if err = lastBkt.Put(commentTS, ref); err != nil {
 			return errors.Wrapf(err, "can't put reference %s to %s", ref, lastBucketName)
 		}
 
@@ -123,7 +123,7 @@ func (b *BoltDB) Create(comment store.Comment) (commentID string, err error) {
 			return errors.Wrapf(err, "can't get bucket %s", comment.User.ID)
 		}
 		// put into individual user's bucket with ts as a key
-		if err = userBkt.Put(commentTs, ref); err != nil {
+		if err = userBkt.Put(commentTS, ref); err != nil {
 			return errors.Wrapf(err, "failed to put user comment %s for %s", comment.ID, comment.User.ID)
 		}
 
diff --git a/backend/app/store/engine/bolt_test.go b/backend/app/store/engine/bolt_test.go
index 66531768..dd30303b 100644
--- a/backend/app/store/engine/bolt_test.go
+++ b/backend/app/store/engine/bolt_test.go
@@ -13,7 +13,7 @@ import (
 	"github.com/umputun/remark42/backend/app/store"
 )
 
-var testDb = "/tmp/test-remark.db"
+var testDB = "/tmp/test-remark.db"
 
 func TestBoltDB_CreateAndFind(t *testing.T) {
 	var b, teardown = prep(t)
@@ -221,13 +221,13 @@ func TestBoltDB_FindForUser(t *testing.T) {
 }
 
 func TestBoltDB_FindForUserPagination(t *testing.T) {
-	_ = os.Remove(testDb)
-	b, err := NewBoltDB(bolt.Options{}, BoltSite{FileName: testDb, SiteID: "radio-t"})
+	_ = os.Remove(testDB)
+	b, err := NewBoltDB(bolt.Options{}, BoltSite{FileName: testDB, SiteID: "radio-t"})
 	require.NoError(t, err)
 
 	defer func() {
 		require.NoError(t, b.Close())
-		_ = os.Remove(testDb)
+		_ = os.Remove(testDB)
 	}()
 
 	c := store.Comment{
@@ -893,9 +893,9 @@ func TestBoltDB_NewFailed(t *testing.T) {
 
 // makes new boltdb, put two records
 func prep(t *testing.T) (b *BoltDB, teardown func()) {
-	_ = os.Remove(testDb)
+	_ = os.Remove(testDB)
 
-	boltStore, err := NewBoltDB(bolt.Options{}, BoltSite{FileName: testDb, SiteID: "radio-t"})
+	boltStore, err := NewBoltDB(bolt.Options{}, BoltSite{FileName: testDB, SiteID: "radio-t"})
 	assert.NoError(t, err)
 	b = boltStore
 
@@ -921,7 +921,7 @@ func prep(t *testing.T) (b *BoltDB, teardown func()) {
 
 	teardown = func() {
 		require.NoError(t, b.Close())
-		_ = os.Remove(testDb)
+		_ = os.Remove(testDB)
 	}
 	return b, teardown
 }
diff --git a/backend/app/store/image/image.go b/backend/app/store/image/image.go
index 11566191..616e0458 100644
--- a/backend/app/store/image/image.go
+++ b/backend/app/store/image/image.go
@@ -12,7 +12,6 @@ import (
 	"encoding/base64"
 	"fmt"
 	"image"
-
 	// support gif and jpeg images decoding
 	_ "image/gif"
 	_ "image/jpeg"
diff --git a/backend/app/store/service/service_test.go b/backend/app/store/service/service_test.go
index 15adc7e6..320d97d6 100644
--- a/backend/app/store/service/service_test.go
+++ b/backend/app/store/service/service_test.go
@@ -1466,13 +1466,13 @@ func Benchmark_ServiceCreate(b *testing.B) {
 
 // makes new boltdb, put two records
 func prepStoreEngine(t *testing.T) (e engine.Interface, teardown func()) {
-	testDbLoc, err := ioutil.TempDir("", "test_image_r42")
+	testDBLoc, err := ioutil.TempDir("", "test_image_r42")
 	require.NoError(t, err)
-	testDb := path.Join(testDbLoc, "test.db")
-	_ = os.Remove(testDb)
+	testDB := path.Join(testDBLoc, "test.db")
+	_ = os.Remove(testDB)
 
 	st := time.Now()
-	boltStore, err := engine.NewBoltDB(bolt.Options{}, engine.BoltSite{FileName: testDb, SiteID: "radio-t"})
+	boltStore, err := engine.NewBoltDB(bolt.Options{}, engine.BoltSite{FileName: testDB, SiteID: "radio-t"})
 	assert.NoError(t, err)
 
 	comment := store.Comment{
@@ -1497,7 +1497,7 @@ func prepStoreEngine(t *testing.T) (e engine.Interface, teardown func()) {
 	t.Logf("prepared store engine in %v", time.Since(st))
 	return boltStore, func() {
 		assert.NoError(t, boltStore.Close())
-		_ = os.Remove(testDb)
+		_ = os.Remove(testDB)
 	}
 }